Workpieces and particularly those formed as castings, forgings, fabrications and by machining often have interior chambers formed therein which have only limited accessibility. Such interior chambers are often shaped and sized so that portions thereof are of significantly larger cross section than any access opening which communicates therewith, and such interior chambers also often include passages or the like which communicate with or project transversely from a main chamber or passage, and as such direct communication with these transverse passages from the access opening is oftentimes difficult or impossible. It is usually necessary to attempt to effect at least some treatment of the walls which define the boundary of the interior chamber in an effort to improve the smoothness and finish thereof, and/or effect removal of debris which may be loosely or firmly attached thereto. This is particularly true when the workpiece is formed as a casting since the core used for defining the interior chamber during the casting process breaks down quickly after pouring and forming of the workpiece, and the material defining the core has to be removed through the access opening, but some material frequently becomes trapped in the interior chamber and/or adheres to the surrounding walls so as to create a poor quality surface.
The treating of the interior chambers of workpieces of this type has involved various techniques such as shaking the workpiece on a vibrator, or injecting streams of fluids such as air or water into the chamber in an attempt to dislodge debris from the chamber or from the walls thereof. This technique, however, is relatively ineffective with respect to creating any significant improvement with respect to the smoothness or quality of the boundary walls.
Because of the difficulties associated with treating (e.g., cleaning, deburring and shot peening) interior walls of chambers defined within workpieces such as castings, in many instances flexible brushes have been inserted, often manually, into the chamber to treat the boundary walls thereof. This technique is partially effective for those boundary walls which communicate with and are accessible from the access opening, but is of little value with respect to those walls which are associated with unusual shapes or transversly projecting regions of the interior chamber. Further, this technique is time consuming and inefficient.
Another technique is disclosed in U.S. Pat. No. 7,063,593 entitled APPARATUS AND PROCESS FOR SURFACE TREATING INTERIOR OF WORKPIECE. This patent discloses using a pair of oppositely facing sprays of cleaning fluid to impinge against each other to force the spray in a perpendicular direction. However, the system of this patent does not work with complex interior geometries.